1. Field of the Invention
The present invention relates to an optical recording medium capable of optically recording record information, an optical recording medium manufacturing apparatus for forming such an optical recording medium and an optical recording medium manufacturing method for forming such an optical recording medium.
2. Description of the Related Art
At present, a reproduction-only DVD-Video disk on which contents are previously recorded and a DVD-RW (DVD Re-recordable) disk as an optical recording medium capable of optically recording record information have been known. FIG. 13 shows a main enlarged view of such a DVD-RW disk and specifically shows an enlarged view of a boundary portion between a buffer zone (area of a direction of an arrow Ba in the drawing) within a read-in area and a control data zone placed in the just front thereof (area of a direction of an arrow Ca in the drawing). Incidentally, for the purpose of making a disk structure easy to understand, in FIG. 13, upper and lower surfaces of the disk are depicted in reverse.
As shown in FIG. 13, according to the DVD-RW disk, in a first area such as the buffer zone or data area in which record information is recorded, groove tracks 1 having a depth Gd [nm] for recording the record information are meanderingly formed and land pre-pits 3 for generating various information such as an address are formed on land tracks 2 located between the adjacent groove tracks 1. Also, according to the DVD-RW disk, in order to prevent an illegal copy of the DVD-Video disk by means of bit by bit, control information recorded thereon is formed into embossed pit rows 4 having the same depth Gd [nm] as that of the groove tracks 1 to be recorded in the control data zone and the groove tracks become an intermittent state.
According to the DVD-RW disk as described above, since the embossed pit rows 4 are embedded in the control data zone, in case that the illegal copy of the DVD-Video disk is made by means of bit by bit, readout of data overwritten in the control data zone is prevented by a reproduction output through the embossed pit rows 4 to disable the illegal copy. However, in the DVD-RW disk constructed thus, the embossed pit rows 4 are formed, so that a radial push-pull signal level in the control data zone (a second area) decreases with respect to a radial push-pull signal level in other first area in which the record information is recorded and a problem of causing instability of operation of a tracking servo circuit or a spindle servo circuit in a recording and reproducing apparatus has arisen.